Radiobiological assessment of permanent implants using tumour repopulation factors in the linear-quadratic model

Rg, Dale

doi:10.1259/0007-1285-62-735-241

Cited by 152 publications

(94 citation statements)

References 6 publications

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“…118,119 This model was used by Ling et al to examine the effect of dose heterogeneity in prostate seed implants. 96 The authors concluded that there might be some advantage in dose heterogeneity at about 20% above the prescribed dose, but beyond that, dose would be ''wasted'' in terms of producing cell kill.…”

Section: Biological Modelsmentioning

confidence: 99%

Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

et al. 1999

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There is now considerable evidence to suggest that technical innovations, 3D image-based planning, template guidance, computerized dosimetry analysis and improved quality assurance practice have converged in synergy in modern prostate brachytherapy, which promise to lead to increased tumor control and decreased toxicity. A substantial part of the medical physicist's contribution to this multi-disciplinary modality has a direct impact on the factors that may singly or jointly determine the treatment outcome. It is therefore of paramount importance for the medical physics community to establish a uniform standard of practice for prostate brachytherapy physics, so that the therapeutic potential of the modality can be maximally and consistently realized in the wider healthcare community. A recent survey in the U.S. for prostate brachytherapy revealed alarming variance in the pattern of practice in physics and dosimetry, particularly in regard to dose calculation, seed assay and time/method of postimplant imaging. Because of the large number of start-up programs at this time, it is essential that the roles and responsibilities of the medical physicist be clearly defined, consistent with the pivotal nature of the clinical physics component in assuring the ultimate success of prostate brachytherapy. It was against this background that the Radiation Therapy Committee of the American Association of Physicists in Medicine formed Task Group No. 64, which was charged ͑1͒ to review the current techniques in prostate seed implant brachytherapy, ͑2͒ to summarize the present knowledge in treatment planning, dose specification and reporting, ͑3͒ to recommend practical guidelines for the clinical medical physicist, and ͑4͒ to identify issues for future investigation.

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Section: Biological Modelsmentioning

confidence: 99%

Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

et al. 1999

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“…Nevertheless, for this evaluation, two-fraction protocols with shorter time delays remain more interesting than a single injection; for evaluation E3, this increase is superior to 8.8% and 5.7% (minimum increases obtained for a 24h time delay) for the MIA and BED mean,TL , respectively, compared with the values obtained for a single injection, and reaches 9.5% and 10.9% for BED mean,TL for time delays superior to 3 and 7 days, respectively. Moreover, the potential of shortening time delays between fractions could be further enhanced by taking into account a repopulation constant for the different ROIs in the calculation of the BED distribution (Dale, 1989). The best number of fractions and time delay between fractions that would keep the absorbed dose rate high enough to compensate for cancerous cell repopulation could then be determined using optimization tools.…”

Section: Discussionmentioning

confidence: 99%

Fractionation protocol design for treatment planning optimization in SIRT using the OEDIPE software

et al. 2014

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-To go further in the optimization of treatment planning in selective internal radiation therapy (SIRT), radiobiological aspects can be accounted for with the OEDIPE software and used to design fractionation protocols. Dosimetry was performed using data from 99m Tc-MAA evaluations of 10 patients treated for hepatic metastases with SIRT. The maximal injectable activity (MIA) was calculated, using a tolerance criterion on BED mean,healthy liver equal to 54 Gy 2.5 , for different fractionation protocols, varying the number of fractions, the repartition of activity and the time delay between fractions. OEDIPE was also used to calculate BED mean and the EUD to the tumoral liver (TL) that would be delivered with those MIAs. Compared with a single-injection protocol, the MIA is increased on average by 23% ± 3%, 36% ± 5% and 45% ± 7% for fractionation protocols with 2, 3 and 4 equal fractions, respectively, while BED mean,TL is increased by 15% ± 2%, 23% ± 4% and 29% ± 5%. EUD TL , calculated for one evaluation, is increased by 51%, 115% and 159% using 2, 3 and 4 equal fractions, respectively. For this evaluation, the optimal activity repartition for twofraction protocols is (3/4 − 1/4) for time delays of less than 4 days, (2/3 − 1/3) for time delays between 4 and 6 days and (1/2 − 1/2) for time delays superior to 6 days. Finally, this study confirmed that OEDIPE can be regarded as a tool for treatment planning optimization and fractionation protocol design in SIRT.

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“…We also recalculated the biologically equivalent dose (BED) of this treatment, taking into account repair and repopulation of breast tissues (14,15), and obtained with an alpha/beta ratio of 10 Gy for early and tumor effects a BED in Gy 10 that is similar to the classical 16 Gy boost in eight fractions. The BED in Gy 3 for late effects in healthy tissues seems, on the other hand, to be higher than for the classical external approach.…”

Section: Discussionmentioning

confidence: 99%

“…When applying this technique for partial breast irradiation, the prescription dose will have to be calculated taking into account the biologic behavior of breast cancer cells (14,15). The BED of a very low dose rate partial breast irradiation should be at least equivalent to the BED of a classical 50 Gy treatment in 25 fractions over 5 weeks.…”

Section: Discussionmentioning

confidence: 99%

Adjuvant stereotactic permanent seed breast implant: A boost series in view of partial breast irradiation

Jansen¹,

Deneufbourg²,

Nickers³

2007

International Journal of Radiation Oncology*Biology*Physics

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Radiobiological assessment of permanent implants using tumour repopulation factors in the linear-quadratic model

Cited by 152 publications

References 6 publications

Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

Permanent prostate seed implant brachytherapy: Report of the American Association of Physicists in Medicine Task Group No. 64

Fractionation protocol design for treatment planning optimization in SIRT using the OEDIPE software

Adjuvant stereotactic permanent seed breast implant: A boost series in view of partial breast irradiation

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